Alex has been ruled out of Brazil's friendly international matches against Iran on Thursday and Ukraine on Monday.
The central defender underwent medical assessment on a thigh muscle injury sustained in the closing moments of Sunday's win over Arsenal, after he had scored Chelsea's second goal.
It is estimated he will be out for three weeks.
Ramires has joined up with the Brazil squad for the two games, the first of which takes place in Abu Dhabi, the second at Derby County's Pride Park.